package demo523;

import java.sql.*;
import java.util.Scanner;

public class LoginDemo {

    private static final String URL = "jdbc:mysql://localhost:3306/usersDb";
    private static final String DB_USERNAME = "root";
    private static final String DB_PASSWORD = "123456";

    /**
     * 登录功能
     */
    public static void main(String[] args) throws ClassNotFoundException, SQLException {
        // 1. 注册（加载）驱动
        Class.forName("com.mysql.cj.jdbc.Driver");

        // 2. 获取数据库连接
        Connection connection = DriverManager.getConnection(URL, DB_USERNAME, DB_PASSWORD);

        // 3. 编写SQL语句
        String sql = "select * from userdb where username = ? and password = ?";

        // 4. 执行SQL语句
        PreparedStatement preparedStatement = connection.prepareStatement(sql);

        // 5. 给问号赋值
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入用户名：");
        String username = scanner.next();
        System.out.println("请输入密码：");
        String password = scanner.next();

        preparedStatement.setString(1, username);
        preparedStatement.setString(2, password);

        // 6. 查询是否有结果的ResultSet，接收查询语句查询出来的结果
        ResultSet resultSet = preparedStatement.executeQuery();

        // 7. 处理结果
        if (resultSet.next()) {
            System.out.println("登录成功！");
        } else {
            System.out.println("登录失败！");
        }

        // 8. 关闭资源
        resultSet.close();
        preparedStatement.close();
        connection.close();
    }
}

